1960s, DLCO, Helium Dilution FRC, Multipurpose Lab System, Spirometer Spirometer, Combination Helium Residual Volume and Single Breath DLCO System, Collins, 1966 July 24, 2017 Richard Johnston Leave a comment From ‘A Catalog of Pulmonary Function Equipment and Accessories’, W. E. Collins Inc., 1966, page 8.